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Dimension of chaotic attractors
Dimension is perhaps the most basic property of an attractor. In this paper we discuss a variety of different definitions of dimension, compute their values for a typical example, and review previous work on the dimension of chaotic attractors. The relevant definitions of dimension are of two general types, those that depend only on metric properties, and those that depend on probabilistic properties (that is, they depend on the frequency with which a typical trajectory visits different regions of the attractor). Both our example and the previous work that we review support the conclusion that all of the probabilistic dimensions take on the same value, which we call the dimension of the natural measure, and all of the metric dimensions take on a common value, which we call the fractal dimension. Furthermore, the dimension of the natural measure is typically equal to the Lyapunov dimension, which is defined in terms of Lyapunov numbers, and thus is usually far easier to calculate than any other definition. Because it is computable and more physically relevant, we feel that the dimension of the natural measure is more important than the fractal dimension.
Date:
September 1, 1982
Creator:
Farmer, J. Doyne; Ott, Edward & Yorke, James A.
System:
The UNT Digital Library
Removal of Silicon from High Level Waste Streams via Ferric Flocculation
The presence of silicate from glass-forming frit in the recycle waste from the Defense Waste Processing Facility (DWPF) produces wastes that when combined with the traditional aluminate-bearing wastes stored in Savannah River Site's tank farms can produce insoluble sodium aluminosilicates. Currently, aluminum-bearing wastes and silicon-bearing wastes are processed in separate evaporators. This, however, limits operational flexibility. Therefore, treatment to remove silicon has been proposed to allow greater flexibility for processing these wastes in the Site's evaporators. The use of a ferric precipitation (flocculation) to remove the silicon has been tested using waste simulants. Ferric precipitation following ferric nitrate addition to two different alkaline DWPF recycle waste simulants was effective at removing silicon to levels below concern for processing in the any of the Savannah River Site's evaporators. Removal of silicon was rapid with removal complete in 2 hours. Elevated temperatures were tested and found to be not required. Capacities of the resultant iron flocculent were approximately 0.1 g of silicon per gram of iron at a final silicon concentration of 50 mg/L. Moreover, the silicon removal obeys a classical Freundlich adsorption isotherm.
Date:
April 7, 2004
Creator:
Wilmarth, W. R.
System:
The UNT Digital Library
Modeling Efforts to Aid in the Determination of Process Enrichment Levels for Identifying Potential Material Diversion
None
Date:
June 5, 2006
Creator:
Guenther, C. F.; Elayat, H. A. & O'Connell, W. J.
System:
The UNT Digital Library
Effect of Nitrate on the Repassivation Potential of Alloy 22 in Chloride Containing Environments.
The study of Alloy 22 was undertaken in several selected nitrate/chloride (NO{sub 3}{sup -}/Cl{sup -}) electrolytes with chloride concentrations [Cl{sup -}] of 1.0, 3.5 and 6.0 molal with [NO{sub 3} {sup -}]/[Cl{sup -}] ratios of 0.05, 0.15 and 0.5 at temperatures up to 100 C. Results showed that the repassivation potentials increased with increase in [NO{sub 3} {sup -}]/[Cl{sup -}] ratio and decreased with increase in temperature. The absolute [Cl{sup -}] was found to have less of an effect on the repassivation potential compared with temperature and the NO{sub 3} {sup -}/Cl{sup -}. Regression analyses were carried out and expressions were derived to describe the relationship between the repassivation potential, temperature, [Cl{sup -}] and [NO{sub 3} {sup -}] for the conditions tested.
Date:
August 16, 2004
Creator:
Ilevbare, G. O.; King, K. J.; Gordon, S. R.; Elayat, H. A.; Gdowski, G. E. & Summers, T. S. E.
System:
The UNT Digital Library
Using computer-based training to facilitate radiation protection review
In a national laboratory setting, it is necessary to provide radiation protection overview and training to diverse parts of the laboratory population. This includes employees at research reactors, accelerators, waste facilities, radiochemical isotope processing, and analytical laboratories, among others. In addition, our own radiation protection and monitoring staffs must be trained. To assist in the implementation of this full range of training, ORNL has purchased prepackaged computer-based training in health physics and technical mathematics with training modules that can be selected from many topics. By selection of specific modules, appropriate radiation protection review packages can be determined to meet many individual program needs. Because our radiation protection personnel must have some previous radiation protection experience or the equivalent of an associate's degree in radiation protection for entry level, the computer-based training will serve primarily as review of major principles. Others may need very specific prior training to make the computer-based training effective in their work situations. 4 refs.
Date:
January 1, 1989
Creator:
Abercrombie, J. S. & Copenhaver, E. D.
System:
The UNT Digital Library
Heavy-section steel technology program: An overview
The major focus of the current irradiation work is on understanding the fracture characteristics of irradiated high-copper weld materials and stainless steel cladding. Testing in the Fifth and Sixth HSST Irradiation Series are underway and include two high-copper weld materials (CU = 0.25 and 0.30%). Both crack initiation and arrest-toughness properties are being investigated. The tests also include Charpy V-notch, tensile, and compact specimens, with the latter ranging in size up to 4TCS for the irradiated high-copper weld materials. The Seventh Irradiation Series is examining the effects of neutron exposure on the fracture properties of stainless steel cladding.
Date:
January 1, 1986
Creator:
Pugh, C. E.
System:
The UNT Digital Library
Constitutive equations for creep analysis of LMFBR components
None
Date:
March 11, 1975
Creator:
Pugh, C. E.
System:
The UNT Digital Library
Constitutive equations for meeting elevated-temperature-design needs
Constitutive equations for representing the inelastic behavior of structural alloys at temperatures in the creep regime are discussed from the viewpoint of advances made over the past decade. An emphasis is placed on the progress that has been made in meeting the needs of the program whose design process is based in part on a design-by-inelastic-analysis approach. In particular, the constitutive equations that have been put into place for current use in design analyses are discussed along with some material behavior background information. Equations representing short-term plastic and long-term creep behaviors are considered. Trends towards establishing improved equations for use in the future are also described. Progress relating to fundamentals of continuum mechanics, physical modeling, phenomenological modeling, and implementation is addressed.
Date:
January 1, 1981
Creator:
Pugh, C. E. & Robinson, D. N.
System:
The UNT Digital Library
Material properties requirements for LMFBR structural design: general considerations and data needs
A statement is given of material properties information needed in connection with the structural design technology for liquid-metal fast breeder reactor (LMFBR) primary circuit components. Implementation of current analysis methods and criteria is considered with an emphasis on data and data correlations for performing elastic-plastic and creep analyses, for establishing allowable stress limits, and for computing creep-fatigue damage. Further development of the technology is discussed in relation to properties information. Emphasis is placed on improved constitutive equations for representing inelastic material behavior, on procedures for treating time-dependent fatigue, and on criteria for creep rupture. The properties are generally discussed without regard to specific alloys, since most categories of information are needed for each major structural material. Some sample experimental results are given for type 304 stainless steel and 2/sup 1///sub 4/ Cr-1 Mo steel.
Date:
January 1, 1977
Creator:
Pugh, C. E. & Purdy, C. M.
System:
The UNT Digital Library
Development of high-temperature structural design methods for liquid-metal fast-breeder reactor system components
None
Date:
October 31, 1973
Creator:
Pugh, C. E.
System:
The UNT Digital Library
HSST crack-arrest studies overview
An overview is given of the efforts underway in the Heavy-Section Steel Technology (HSST) Program to better understand and model crack-arrest behavior in reactor pressure vessel steels. The efforts are both experimental and analytical. The experimental work provides K/sub Ia/ data from laboratory-sized specimens, from thick-wall cylinders which exhibit essentially-full restraint and from nonisothermal wide-plate specimens. These data serve to define toughness-temperature trends and to provide validation data under prototypical reactor conditions. The analytical efforts interpret and correlate the data, plus provide LEFM, elastodynamic and viscoplastic methods for analyzing crack run-arrest behavior in reactor vessels. The analysis methods are incorporated into finite element computer programs which are under development at three separate laboratories. 22 refs., 10 figs.
Date:
January 1, 1985
Creator:
Pugh, C. E. & Whitman, G. D.
System:
The UNT Digital Library
Dust Monitoring on the Hanford Site: An Investigation into the Relationship Between TSP, PM-10, and PM-2.5
High levels of particulate matter (PM) are linked to some health problems and environmental issues. Air quality standards have been developed in hopes to reduce particulate matter problems. The most common fractions of particulate matter measured include PM2.5, PM10, and total suspended particles (TSP). The focus of this study was to evaluate relationships between PM2.5, PM10, and TSP concentrations specific to the Hanford Site, near Richland, Washington. Measurements of PM2.5 and PM10 concentrations continued while additional measurements of TSP were made over several summer months. Four sampling locations on the Hanford Site were used to compare spatial differences in the data. Comparison of the data revealed a strong linear correlation between PM10 and TSP for the time period evaluated. The correlation between PM2.5 and TSP was not as strong, and indicated that local sources rarely were above background measurements. This was supported by the correlation of ground level PM2.5 with PM2.5 concentrations measured on a near by mountain.
Date:
January 1, 2004
Creator:
Schwartz, Tara & Fitz, Brad G.
System:
The UNT Digital Library
Integration of wide-plate crack-arrest test results
The primary objective of the crack-arrest studies under the Heavy-Section Steel Technology (HSST) Program is to generate data for understanding the crack-arrest behavior of prototypical pressure vessel steels at temperatures near and above the onset of the Charpy uppershelf region. Specific program goals are to: (1) extend existing K/sub Ia/ data bases to temperatures beyond those associated with the upper limit in the ASME BandPVC; (2) clearly establish that crack-arrest occurs prior to fracture-mode conversion; (3) observe the relationship between arrest data and machine/specimen compliance behavior; and (4) validate the predictability of crack arrest, stable tearing, and/or unstable tearing sequences for ductile materials. In meeting these goals, the HSST program is generating crack-arrest data over an expanded temperature range through tests involving large thermally-shocked cylinders, pressurized-thermally-shocked vessels and wide-plate specimens. This presentation will focus on data from the wide-plate specimens which have the advantage that a more significant number of data points can be obtained at affordable costs.
Date:
October 1, 1986
Creator:
Pugh, C. E. & Naus, D. J.
System:
The UNT Digital Library
For the Record [Fall 2015]
For the Record section for Fall 2015, including the minutes of the regular quarterly board meeting of the Board of Directors of the Oklahoma Historical Society that was held on April 22, 2015, as well as the minutes of the annual meeting of the membership that was held on April 23, 2015. It also includes two OHS special board meetings, the first occurring on April 23, 2015 and the second occurring on June 10, 2015.
Date:
Autumn 2015
Creator:
Oklahoma Historical Society
System:
The Gateway to Oklahoma History
SNEAP 78: symposium of Northeastern accelerator personnel
Session topics of the symposium include: tubes, vacuum, and conditioning; gaseous insulation and gas handling systems; charging systems; safety; ion sources; projects recently completed or under construction; stripping; beam transport; control systems; and telemetry. Twenty eight items were included separately in the data base. (GHT)
Date:
June 1, 1979
Creator:
Bair, J. K. & Jones, C. M.
System:
The UNT Digital Library
Growth and stability of oxidation resistant Si nanocrystals formed by decomposition of alkyl silanes
The synthesis and characterization of 1-10 nm Si nanocrystals highly resistant to oxidation is described. The nanocrystals were prepared by thermal decomposition of tetramethylsilane at 680 C, or in a gold- induced catalytic process at lower temperatures down to 400-450 C using trioctylamine as an initial solvent. Transmission electron microscopic analysis of samples obtained in the presence of gold show that the nanocrystals form via solid-phase epitaxial attachment of Si to the gold crystal lattice. The results of computational modeling performed using first principles density functional theory (DFT) calculations predict that the enhanced stability of nanocrystals to oxidation is due to the presence of N or N-containing groups on the surface of nanocrystals.
Date:
January 12, 2007
Creator:
Zaitseva, N.; Hamel, S.; Dai, Z. R.; Saw, C.; Williamson, A. J. & Galli, G.
System:
The UNT Digital Library
A comparison of high-speed links, their commercial support and ongoing R D activities
Technological advances and a demanding market have forced the development of higher bandwidth communication standards for networks, data links and busses. Most of these emerging standards are gathering enough momentum that their widespread availability and lower prices are anticipated. The hardware and software that support the physical media for most of these links is currently available, allowing the user community to implement fairly high-bandwidth data links and networks with commercial components. Also, switches needed to support these networks are available or being developed. The commercial suppose of high-bandwidth data links, networks and switching fabrics provides a powerful base for the implementation of high-bandwidth data acquisition systems. A large data acquisition system like the one for the Solenoidal Detector Collaboration (SDC) at the SSC can benefit from links and networks that support an integrated systems engineering approach, for initialization, downloading, diagnostics, monitoring, hardware integration and event data readout. The issue that our current work addresses is the possibility of having a channel/network that satisfies the requirements of an integrated data acquisition system. In this paper we present a brief description of high-speed communication links and protocols that we consider of interest for high energy physic High Performance Parallel Interface (HIPPI). Serial …
Date:
October 1, 1992
Creator:
Gonzalez, H. L.; Barsotti, E.; Zimmermann, S.; Nomachi, M. & Sasaki, O.
System:
The UNT Digital Library
Optical Properties of CdSe Nanoparticle Assemblies
We report on three-dimensional fluorescence imaging of micron-size faceted crystals precipitated from solutions of CdSe nanocrystals. Such crystals have previously been suggested to be superlattices of CdSe quantum dots [1,2]. Possible applications for these materials include their use in optical and optoelectronic devices. The micron-size crystals were grown by slow evaporation from toluene solutions of CdSe nanocrystals in the range of 3-6 nm, produced by traditional wet-chemistry techniques. By using a confocal microscope with laser illumination, three-dimensional raster-scanning and synchronized hyper-spectral detection, we have generated spatial profiles of the fluorescence emission intensity and spectrum. The fluorescence data of the micro-crystals were compared with spectra of individual nanocrystals obtained from the same solution. The results do not support the assertion that these microcrystals consist of CdSe superlattices.
Date:
November 24, 2003
Creator:
Huser, Thomas; Gerion, Daniele; Zaitseva, Natalia; Krol, Denise M. & Leon, F. Rafael
System:
The UNT Digital Library
Two-dimensional computer simulation of hypervelocity impact cratering: some preliminary results for Meteor Crater, Arizona
A computational approach used for subsurface explosion cratering has been extended to hypervelocity impact cratering. Meteor (Barringer) Crater, Arizona, was selected for our first computer simulation because it was the most thoroughly studied. It is also an excellent example of a simple, bowl-shaped crater and is one of the youngest terrestrial impact craters. Shoemaker estimates that the impact occurred about 20,000 to 30,000 years ago (Roddy (1977)). Initial conditions for this calculation included a meteorite impact velocity of 15 km/s. meteorite mass of 1.57E + 08 kg, with a corresponding kinetic energy of 1.88E + 16 J (4.5 megatons). A two-dimensional Eulerian finite difference code called SOIL was used for this simulation of a cylindrical iron projectile impacting at normal incidence into a limestone target. For this initial calculation a Tillotson equation-of-state description for iron and limestone was used with no shear strength. A color movie based on this calculation was produced using computer-generated graphics. Results obtained for this preliminary calculation of the formation of Meteor Crater, Arizona, are in good agreement with Meteor Crater Measurements.
Date:
April 1, 1978
Creator:
Bryan, J. B.; Burton, D. E.; Cunningham, M. E. & Lettis, L. A., Jr.
System:
The UNT Digital Library
Experimental studies of a large heterogeneous LMFBR benchmark core, ZPPR-13A
The ZPPR-13 program provides basic physics information for testing calculations of radially heterogeneous cores of about 700 MWe size. ZPPR-13 is part of the JUPITER cooperative program between Japan and the US. The results are presented of measurements and analysis for the first assembly, ZPPR-13A. These are the first data for heterogeneous cores of this size available in the US and complement results from ZPPR-9, a conventional LMFBR of similar size.
Date:
May 27, 1983
Creator:
Brumbach, S. B.; Collins, P. J.; Carpenter, S. G.; Suzuki, S. & Kawashima, M.
System:
The UNT Digital Library
Interaction of molecular beams with solid surfaces
From proceedings of the International Summer Institute in surface science; Milwaukee, Wisconsin, USA (28 Aug 1973). Molecular beam - surface scattering experiments, the nature of elastic and inelastic scattering, and the information obtained from detection of the angular distribution and kinetic energy of the scattered particles are described. The types of energy exchange that take place between a gas atom or molecule and the surface atoms and the theories that have been developed to explain some of these energy transfer processes are discussed. Finally the results of some experiments are reviewed, and directions for future research are pointed out. (JFP)
Date:
August 1, 1973
Creator:
Somorjai, G. A. & Brumbach, S. B.
System:
The UNT Digital Library
Benchmark physics tests in the metallic-fuelled assembly ZPPR-15
Results of the first benchmark physics tests of a metallic-fueled, demonstration-size, liquid metal reactor are reported. A simple, two-zone, cylindrical conventional assembly was built with three distinctly different compositions to represent the stages of the Integral Fast Reactor fuel cycle. Experiments included criticality, control, power distribution, reaction rate ratios, reactivity coefficients, shielding, kinetics and spectrum. Analysis was done with 3-D nodal diffusion calculations and ENDFIB-V.2 cross sections. Predictions of the ZPPR-15 reactor physics parameters agreed sufficiently well with the measured values to justify confidence in design analyses for metallic-fueled LMRs.
Date:
January 1, 1987
Creator:
McFarlane, H. F.; Brumbach, S. B.; Carpenter, S. G. & Collins, P. J.
System:
The UNT Digital Library
Autoradiographic inventory methods
Described are autoradiographic techniques which can verify the number and SNM content of plutonium- and uranium-containing fuel elements. These techniques are applied to fast critical assembly fuel and to low-enriched uranium in LWR fuel assemblies. Autoradiographic images are formed by the spontaneously emitted X and gamma rays from the fuel elements striking X-ray film in contact with the fuel elements or their containers. Autoradiography allows a large number of items to be examined in a minimum inspection time and with minimum facility impact. Results are presented for fast critical assembly fuel in a variety of storage modes as well as in fast critical assemblies themselves. Results are also presented for low-enriched uranium rods in unirradiated LWR fuel assemblies. In all cases, missing fuel elements or substitution of elements containing inert material or depleted uranium were detected. (6 figs.)
Date:
January 1, 1978
Creator:
Brumbach, S. B. & Perry, R. B.
System:
The UNT Digital Library
Autoradiography as a safeguards technique
Autoradiography gives a simultaneous piece count and attribute check for special nuclear material without, however, a quantitative measurement of fissile material. Applications to fuel elements containing plutonium for fast critical assemblies or uranium for LWRs are discussed. 15 figures.
Date:
January 1, 1978
Creator:
Brumbach, S. B.
System:
The UNT Digital Library